Do I Need a Switchboard Upgrade

The line item that turns up on install day

The complaint we hear most often about other people’s quotes is not the price. It is the electrical work that appeared once the job had started, when the wall was already open and there was no sensible way to say no.

That situation is avoidable. The supply side of an air conditioning installation can be assessed before anyone commits, and it should be, because whether your switchboard needs work is knowable in about ten minutes with the cover off.

What a new system needs from the supply

Most split systems are wired on their own dedicated final subcircuit rather than sharing a power circuit with the rest of the room. That is not an installer preference. A compressor draws a substantial starting current, and sharing that with general power points causes nuisance tripping and voltage sag at best.

Any new final subcircuit added to an installation has to have residual current protection under the wiring rules. That single requirement is what quietly escalates a lot of jobs, and it is worth understanding before you get quotes. If your board is a row of rewirable ceramic fuses, there is no RCD in it and usually nowhere to fit one, so adding a compliant circuit means changing the board rather than adding a breaker to it. A job that sounded like one circuit becomes a board replacement, and no aircon quote in the world includes that unless someone looked first.

What we tend to find in older Cairns homes

Ceramic rewirable fuse boards are still common in houses that have not been renovated, and they are the clearest trigger. So are boards that have already been filled by a previous renovation, a hot water changeover and a solar inverter, leaving no physical space on the busbar.

Pre 1990s boards often have asbestos containing backing panels. That is not a disaster and it is routinely handled, but it is specialist work, and it has to be identified rather than discovered.

Then there is condition. Corroded terminals, heat damage on a neutral bar and undersized or perished consumer mains all show up in coastal homes, and none of them are things a competent electrician will build a new circuit on top of.

Take the cover photo off your board, or just photograph the front of it, and send it through. That is usually enough to tell you which row you are in before anyone visits.

Single phase, three phase and the demand question

Most Cairns houses are single phase, and a single phase supply runs a split system or a modest ducted system without difficulty. It is the accumulation that gets people. Add a multi head system or a decent ducted unit to a house that already has an electric hot water system, an oven, a pool pump and a workshop, and the maximum demand calculation can exceed what the consumer mains are rated for. Larger ducted and light commercial equipment is sometimes three phase in its own right.

The honest answer is that many installs need no electrical upgrade at all, some need a breaker and an RCD, and a few need a new board. All three are fine. What is not fine is finding out on the day.

We check the board and the supply as part of quoting split system installation in Cairns, and if electrical work is needed it appears in the written quote with the rest of the job. Call 0489 266 523 if you already suspect your board is the problem.